Fusible switch



Aug. 29, 1967 H, STANBACK ET AL 3,339,119

y FUSIBLE SWITCH Filed sept. 23, 1964 i 4 sheets-sheet 1 ug. 29, 1967 H,L STANBACK ET A1. 3,339,1 19

FUSIBLE SWITCH jfj /ZE 45@ 45. 43a, m

Filed sept, 23, 1964 4 sheets-Sheet z 43 6 43C 63 @Al u IN VENTORS ug.29, 1967 H` STANBACK ET AL 3,339,119

FUSIBLE SWITCH Filed Sept. 23, 1964 I NVE N TORS 1% ff/@7111561.25Z/zac/d Aug. 29, 1967 H. sTANBAcK r-:TAL 3,339,119

FUSIBLE SWITCH Filed Sept. 23, 1964 4 Sheets-Sheet 4 United StatesPatent tlice 3,33 9,1 19 Patented Aug. 29, 1967 3,339,119 FUSIBLE SWITCHHarris I. Stanback and Harold H. Downs, Lexington, Ky.,

and Melvin J. George, Ferndale, Mich., assignors to Square D Company,Park Ridge, Ill., a corporation of Michigan Filed Sept. 23, 1964, Ser.No. 398,638 9 Claims. (Cl. 317-116) This invention relates generally tofusible switches, and more particularly 'to fusible switches ofsubstantially the saine size and shape as automatic electric circuitbreakers so as to be interchangeable therewith in electricalpanelboards.

Objects of the invention include the following:

(a) To provide an improved fusible switch for an electrical panelboard;

(b) To provide a fusible switch including a movable switch handle formedof electrically insulating material, and an electrically conductivecombination fuse clip and movable contact secured to an inner endportion of the switch handle and having a fuse clip portion which isadapted to receive and electrically engage an end portion of a cartridgefuse and a movable contact portion which is adapted to complete acircuit through a cartridge fuse held by the fuse clip portion;

(c) To provide a fusible switch including a stationary contact, a switchhandle formed of electrically insulating material and turnable to on andoli positions, an electrically conductive combination fuse clip andmovable contact secured to an inner end portion of the switch handle andhaving a fuse clip portion which is adapted to receive and electricallyengage an end portion of a cartridgel fuse and a movable contact portionwhich engages the stationary contact in the on position of the switchhandle, and a single spring member cooperable with the switch handle andacting both as an indexing spring in the turning of the switch handlebetween 'the on and off positions and as a contact pressure springexerting pressure between the stationary contact and the movable contactportion in the on position of the switch handle;

(d) To provide a fusible switch including a stationary contact, amovable switch handle formed of electrically Ainsulating material, anelectrically conductive combination fuse clip and movable Contactsecured to an inner end portion of the switch handle and having afuseclip portion which is adapted to receive and electrically engage an endportion of a cartridge fuse and a movable contact portion which isengageable with the stationary contact, and a spring member engaging theswitch handle from the side thereof opposite the movable contact portionand establishing pressure between the stationary contact and the movablecontact portion when the movable contact portion is in engagement withthe stationary contact, the switch handle and a cartridge fuse acting asa rigid lever member when an end port1on of a cartridge fuse isinstalled in the fuse clip portion, and the spring member tending torotate the ridge lever member formed by the switch handleand cartridgefuse about the other end portion of the cartridge fuse and beingdisposed farther from the other end portion of the cartridge fuse thanthe movable contact portion so as to possess a mechanical advantagethereover and increase the pressure between the stationary contact andthe movable contact portion;

(e) To provide a fusible switch including a casing molded ofelectrically insulating material, a switch handle formed of electricallyinsulating material and being re'- movably insertable in the casing, anelectrically conductive fuse clap secured to an inner end portion of theswitch handle and adapted to releasably receive and electrically engagean end portion of a cartridge fuse, and means insuring removal of a fusefrom the casing when the fuse has been installed in the fuse clip, andthe switch handle, fuse clip, and fuse have been inserted in the casingand the switch handle and fuse clip are thereafter removed from thecasing;

(f) To provide a plurality of fusible switches respectively adapted toreceive a plurality of fuses of dilferent first, second, and thirdcurrent ratings, each of the switches including a casing molded ofelectrically insulating material, a stationary contact in the casing, aswitch handle formed of electrically insulating material, and anelectrically conductive combination fuse clip and movable contactsecured to an inner end portion of the switch handle and having a fuseclip portion which is adapted to receive and electrically engage an endportion of a cartridge fuse and a movable contact portion which engagesthe stationary contact in an on position of the switch handle and isdisengaged from the stationary contact in an o position of the switchhandle, the switch handle being removably insertable in the casing andturnable to the on and olf positions, and rejection means preventing anyone of the switch handles of the fusible switches respectively adaptedto receive fuses of the rst, second, and third current ratings frombeing turned to the on position in the casing of the fusible switchadapted to receive a fuse of the second current rating when it has anend portion of a cartridge fuse of the first current rating received inthe fuse clip portion of the combination fuse clip and movable contactsecured thereto, preventing the switch handles of the fusible switchesrespectively adapted to receive fuses of the iirst and secf ond currentratings from being turned to the on position in the casing of thefusible switch adapted to receive a fuse of the third current rating,and preventing the switch handle of the fusible switch adapted toreceive a fuse of the third current rating from being turned to the onposition in the casing of the fusible switch adapted to receive a fuseof the third current rating when it has an end portion of a cartridgefuse of one of the first and second current ratings received in the fuseclip portion of the combination fuse clip and movable contact securedthereto;

(g) To provide a fusible switch including a movable switch handle formedof electrically insulating material and an electrically conductivecombination fuse clip and a pair of movable contacts secured to an innerend portion of the switch handle and having a fuse clip portion which isadapted to receive and electrically engage an end portion of a cartridgefuse, a lirst movable contact portion which is adapted to complete acircuit through a cartridge fuse held by the fuse clip portion, and asecond movable contact portion which is adapted to complete a -circuitthrough an indicating lamp;

(h) To provide a fusible switch including a stationary contact, a switchhandle formed of electrically insulating material and turnable to on andoli positions, an electrically conductive combination fuse clip and pairof movable contacts secured to an inner end portion of the switch handleand having a fuse clip portion which is adapted to receive andelectrically engage an end portion of a cartridge fuse and a rst movablecontact portion which engages the stationary contact in the on positionof the switch handle, an indicating lamp, and a spring member cooperablewith the switch handle and acting as an indexing spring in the turningof the switch handle between the on and off positions, a second movablecontact portion of the combination fuse clip and pair of movablecontacts engaging the spring member in the on position of the switchhandler to complete a circuit through the indicating lamp; and

(i) To provide a fusible switch including a casing molded ofelectrically insulating material, a stationary contact in the casing, aswitch handle formed of electrically insulating material and turnable inthe casing to on and off positions, an electrically conductivecombination fuse clip and pair of movable contacts secured to an innerend portion of the switch handle and having a fuse clip portion which isadapted to receive and electrically engage an end portion of a cartridgefuse and a rst movable contact portion which engages the stationarycontact in the on position of the switch handle, a spring member in thecasing cooperable with the switch handle and acting as an indexingspring in the turning of the switch handle between the on and offpositions, a load terminal strap in the casing having an outer endportion serving as a part of a load terminal, an inner end portionadapted to electrically engage the other end portion of the cartridgefuse, and an intermediate portion having a resilient offset tongueportion, and an indicator lamp in the casing having a rst lead wireelectrically connected to the spring member and another lead wireelectrically -connected to the resilient offset tongue portion of theload terminal strap by entrapment between the resilient offset tongueportion and a portion of the casing, a second movable contact portion ofthe combination fuse clip and pair of movable contacts engaging thespring member in the on position ofthe switch handle.

Other objects and advantages of the invention will appear when thefollowing specification is considered along with the' accompanyingdrawings, in which:

FIG. 1 is a side elevational View of a fusible switch constructed inaccordance with the invention;

FIG. 2 is a fragmentary enlarge top view of the fusible switch of FIG.1, the combination fuse clips and movable contacts being shown in brokenlines without fuses in the fuse clip portions thereof;

FIG. 3 is an enlarged view similar to FIG. 1, but with the cover of thefusible switch removed, showing fuses installed therein;

FIG. 4 is an enlarged view of one of the switch handle and combinationfuse clip and movable contact assemblies of the fusible switch of FIGS.1, 2, and 3, looking at the inner end thereof;

FIG. 5 is a perspective view of the line terminal and stationary contactassembly of the fusible switch of FIGS. 1, 2, and 3;

FIG. 6 is a sectional view of the fusible switch of FIG. 1 takengenerally along the line 6-6 of FIG. 3;

FIG. 7 is an elevational view of a fuse and one of the switch handle andcombination fuse clip and movable contact assemblies of the fusibleswitch of FIG. 1, showing the fuse' in solid lines tilted for removalfrom or insertion into the fuse clip portion, and in broken lines fullyinstalled in the fuse clip portion;

FIG. 8 is a view taken from the right of FIG. 7, but omitting the fuse;

FIG. 9 is a perspective view of the combination fuse clip and movablecontacts of one of the switch handle' and combination fuse clip andmovable Contact assemblies ofthe fusible switch of FIG. 1;

FIG. 10 is a perspective view of one of the handle index and contactpressure springs of the fusible switch of FIG. 1;

FIGS. l1, 12, and 13 are views illustrating a system ofnon-interchangeability for ditferently rated fusible switches, fuses andswitch handles constructed in accordance with the invention, thecombination fuse clips and movable contact assemblies being omitted forclarity, the bases of the fusible switches being shown fragmentarily,the fuses and switch handles being shown partially inserted into theirrespective bases, which are arranged in order of decreasing currentrating, and the switch handles being shown midway between on and offpositions;

FIG. 14 is a circuit diagram for the fusible switch of FIG. 1.

FIG. 15 is a fragmentary front view of an electrical panelboard havingfusible switches constructed in accordance with the invention andelectrical circuit breakers interchangeably mounted thereon; and

FIG. 16 is a sectional view taken generally along the line 16-16 of FIG.15.

A fusible switch 20 constructed in accordance with the invention isshown in FIGS. 1 and 2. The switch 20 includes a casing molded ofinsulating material and having a base portion 22 and a cover portion 24which are generally symmetrical but which have certain importantdifferences hereinafter described. The base portion 22 and the coverportion 24 are held together preferably by -a plurality of rivets 26 andeach is provided with a plurality of inner projections and wall portionsfor entrapping various parts of the fusible switch such as a lineterminal and stationary contact assembly 28, a pair of load terminalstraps 29 and 30, a pair of resilient, pushin type connector springs 32,a pair of handle index and contact pressure springs 34, a pair ofindicator lamps 36, a pair of resistors 38, and a mounting clip 40.

Removably mounted in the casing for pivotal movement between on and 01Tpositions are -a pair of switch handle and combination fuse clip andmovable contact assemblies 42 each including a switch handle 43 and amember 44 which is `a combination fuse clip and pair of movable contactsand is best shown in FIG. 9. Each member 44 is adapted to receive an endportion or ferrule of a cartridge fuse 46. The line terminal andstationary contact assembly 2S is best shown in FIG. 5 and includes aterminal strap 48 received in a groove in the base portion 22 as shownin FIG. 6 and shaped to provide a pair of stationary contact portions48a. An olfset end portion 48h of the terminal strap 48 is riveted orotherwise secured between inner end portions 49a and 50a of a pair ofplug-in jaws 49 and 50 having central portions 491; and 50]; which areriveted or otherwise secured to each other.

The casing Iformed by the base portion 22 and the cover portion 24 is ofsubstantially the same size as the casing of the circuit breakerdisclosed in U.S. Patent No. 3,134,051, and the distance between themounting clip 40 and the line terminal formed by the jaws 49 and 50 issubstantially the same as the distance between the mounting clip andplug-in line terminal of the circuitv breaker, whereby the fusibleswitch is interchangeable with the circuit breaker in an electricalpanelboard.

The load terminal straps 29 and 30 are provided respectively with a pairof outer end portions 29a and 30a which form a pair of load terminals.The casing is provided with a pair of apertures 52 for respectivelyreceiving a pair of load wires 53 and with a pair of apertures 54 forselectively receiving a screw driver or other tool in order to depressthe respective resilient connector spring 32 inwardly to release theespective load wire 53. As will be understood, the load wires 53 may beconnected simply by pushing them respectively between the outer endportions 29a `and 39a and the 4associated resilient connector springs32.

The load terminal straps 29 and 30 are respectively provided with a pairof contoured inner end portions 29b and 30h each of which is shaped toreceive and electrically engage the other end portion or ferrule of therespective cartridge fuse 46 on only one side thereof and to hold theother side thereof against a portion of the casing. The end portions 29hand 3011 thus form a pair of one-sided fuse clips. The intermedi-ateportions of the terminal straps 29 and 30 are respectively provided withresilient offset tongue portions 29e` and 30e. Each indicator lamp 36 isprovided with a lead wire 56 which is electrically connected to arespective one of the resistors 38, and a lead wire 57 which iselectrically connected to a respective one of the springs 34. Further,the resistors 38 are electrically connected respectively to the loadterminal straps 29 and 30 by a pair of wires S9 and 60 trappedrespectively between the resilient tongue portions 29C and 30r.` andportions of the base portion 22 of the casing. The wire 56 which extendsacross the terminal strap 48 is provided with an insulating sheath 61.

The handle index and cont-act pressure springs 34 are formed from flatstrip s-tock and are shaped as best shown in FIG. 10. Each spring 34includes a at end portion 34a confined in a respective appropriaterecess in the base portion 22 and serving as -an anchoring leg, and anintermediate relatively sharply curved anchoring nose portion 34breceived in a respective appropriate recess (not shown) in the coverportion 24. The anchoring leg 34a of each spring may be provided withappropriate slots such as indicated at 34e for retaining the respectivewire 57, which is electrically connected to the spring 34 preferably byentrapment between the anchoring leg 34a and the base portion 22. Theend portion of each spring 34 opposite the anchoring leg 34a is split toprovide a stationary cont-act portion 34d cooperable with a movablecontact portion 44a of a respective one of the combination fuse clip andmovable contact members 44, which are shaped as best shown in FIG. 9.Between the split end portion and the anchoring nose portion 34b, eachspring 34 is curved through an obtuse angle to provide a handle indexand contact pressure establishing portion 34e cooperable with aprojecting portion 43a of a respective one of the switch handles 43 toindex the switch handle in the turning thereof to on and off positionsand to establish pressure in the on position of the handle between therespective stationary contact portion 48a and a movable contact portion44b of the respective member 44.

Each member 44 includes a fuse clip portion 44e received in a suitablerecess in an inner end portion of one of the switch handles 43 andadapted to receive an end portion or ferrule of one of the cartridgefuses 46. Each switch handle 43 is provided with an axially extendinggroove 43h the inner end portion of which intercepts the recess in theinner end portion of the switch handle in which the respective fuse clipportion 44C is received, and each fuse clip portion 44a` is providedwith an outwardly extending resilient tongue portion 44d which projectsinto the respective groove 43b to retain the member 44 in the recess inthe respective switch handle 43 by engagement with the surface definingthe inner end of the groove 43b. Each member 44 is also provided with aninwardly extending projection 44e formed in any suitable manner andspaced from the fuse clip portion 44e` to prevent removal of a fuse 46,while the longitudinal axes of the fuse and of the respective switchhandle 43 are collinear, by interfering with an edge 46a of a ferrule46b of the fuse 46 (FIG. 7). Thus, when a switch handle 43 is removedfrom the casing, a fuse 46 associated with the respective member 44 willalso be removed therewith rather than being retained in the casing byone of the inner end portions 29h or 30!) of a load terminal strap.However, a fuse 46 can be inserted in or removed from a fuse clippor-tion 44C if it is tilted or cocked with respect to the axis of therespective handle 43, so that the edge 46a of the fuse ferrule 46bclears the projection 44e, as shown in FIG. 7 by the solid-line positionof the fuse. The tilting of the fuse 46 is accommodated by the provisionof a notch 44f in the fuse clip portion 44 (FIG. 9) and a notch 43d inthe switch handle 43 (FIG. 6), the notch 43d also accommodating themovable contact portion 44a and the notch 441 resulting from the formingof the movable contact portion 44a and being opposite the projection44e.

The casing formed by the base portion 22 and cover portion 24 isprovided with two sets of suitable on and olf indi-cia as shown in FIG.2, and outer end portions 43e of the respective switch handles 43 areshaped to provide easy gripping by an operator as well as to deiinepointers for the respective sets of on and oit indicia. The switchhandles 43 are turnable in the casing to the on and oft positions, itbeing understood that in the on position of a switch handle, the contactportion 44b 0f th respective member 44 will be in engagement with therespective contact portion 48a of the terminal strap 48 and the contactportion 44a of the respective member 44 will be in engagement with thecontact portion 34d of the respective spring 34, and that in oifposition of the switch handle, these cooperable contact portions will beout of engagement.

As indicated at 62 in FIGS. 2 and 3, enoughclearance may be providedbetween a switch handle 43 in the on position thereof and the casingformed by the base portion 22 and the cover portion 24 so Ithat theswitch handle 43 and the fuse 46 installed therein act as a single rigidmember tending to turn counterclockwise, as viewed in FIG. 2, about theinner end portion of the fuse 46, as a result of the force of therespective spring 34, which is disposed farther from the inner end ofthe fuse 46 than the respective stationary contact portion 48a andmovable contact portion 44b and thus has a mechanical advantage withrespect thereto to increase the Contact pressure therebetween.Alternatively, the base portion 22, cover portion 24, and switch handles43 may be constructed without clearance, as at 62, ltherebetween in theon position of the switch handles. Without such clearance, a switchhandle 43 and fuse 46 do not act as a single rigid member, and theswitch handle 43 tends to turn clockwise, as viewed in FIG. 2, about itsouter end portion, as a result of the force of the respective spring 34,which is disposed closer to the outer end portion of the switch handle43 than the respective stationary contact portion 48a and movablecontact portion 44b so as to have no mechanical advantage with respectthereto, but nevertheless provides adequate Contact pressuretherebetween.

Means are provided for preventing insertion and removal of a switchhandle 43 from the casing while it is in the on position with respectthereto. As shown in FIGS. 2 and 6, the base portion 22 and coverportion 24 are shaped differently adjacent the respective switch handles43, the portions of the handle-receiving openings in the cover portion24 being substantially semi-circular, as at a pair of semi-circularsurfaces 63 shown in FIG. 2, so as not to accommodate the projectingportion 43a of a switch handle, but the portions of the handle-receivingopenings in the base portion 22 being squared olf, as at pairs ofsurfaces 64 and 65 shown in FIG. 2, to accommodate the projectingportion 43a of a switch handle. Thus, a switch handle 43 may be insertedin the casing only in a rela-tive angular position in which theprojecting portion 43a is received in one of the squared oif portions ofthe handle-receiving openings, as defined by a pair of the surfaces 64and 65 in the base portion 22, and this position corresponds to the olfposition of a switch handle 43, as shown for the right-hand switchhandle in FIG. 2. However, inside the casing, the portions of the coverportion 24 defining the semi-circular surfaces 63 end, as at a pair ofsurfaces 66, one of which is shown in FIG. 6, and the portions of thebase portion 22 delining the surfaces 65 end, as at a pair of surfaces67 shown in FIG. 3. When the projecting portion 43a of a switch handle43 is entirely inwardly of the respective surfaces 66 and 67, it is nolonger completely restrained and the handle may be turned to the onposition, as shown for the left-hand switch handle in FIG. 2. To removea switch handle from the casing, it must irst be turned to the offposition to dispose the projecting portion 43a adjacent the respectivesurface 64 of the base portion 22 and out of interfering relationshipwith the respective surface 66 of the cover portion 24 and therespective surface 67 of the base portion 22.

FIG. 14 shows the circuit diagram for the fusible switch of FIGS. 1-3,the numerals for the electrical symbols being identical to the numeralsof the 7 corresponding mechanical structures as described in FIGS. 1-10.

FIGS. 11-13 illustrate a system of non-interchangeability for fusibleswitches respectively adapted to receive fuses of three differentratings, including means preventing -th-e effective installation of afuse of a higher current rating than the current rating of a fuseintended for the particular switch. Thus, FIG. l1 shows a base portion12211 for a switch adapted to receive a fuse having the highest of threediffe-rent current ratings, FIG. 13 shows a base portion 122C for aswitch adapted to receive a fuse having the lowest of the three currentratings, and FIG. 12 shows a base portion 122b for a switch adapted toreceive a fuse having the intermediate of the three current ratings, thebase portions being shown fragmentarily and the interal parts of theswitches being omitted for clarity. FIG. 11 also shows a fuse 14611 ofthe highest current rating and a switch handle 14311 intended for usewith the switch having the base portion 12211, FIG. 12 shows a fuse 146bof the intermediate current rating and a switch handle 14317 intendedfor use with the switch having the base portion 12.2b, and FIG. 13 showsa fuse 146C of the lowest current rating and a switch handle 143Cintended for use with the switch having the base portion 122e. Thecombination fuse clips and movable contacts of the switch handles 14311,143b, and 143C are omitted for clarity.

In accordance with the invention, rejection means are providedpreventing the turning of a switch handle having one of the fuses 14611and 146b mounted therein to an on position in the switch having the baseportion 122C and preventing the turning of a switch handle having a fuse14611 mounted therein to an on position in the switch having the baseportion 122b.

The fuses 14611, 146k, and 146C are of the same diameter, but the fuse14611 is longer than the fuse 14611, and the fuse 146b is longer thanthe fuse 146e. The fusible switches having the bases 12211, 122b, and122C are of the same physical size and outer shape. The switch handles14311, 1-43b, and 143C are of the same diameter and the same overalllength, but the recesses therein opposite the gripping and pointerportions 43e for receiving fuses are of different effective depths, thefuse 14611 projecting farther into the switch handle 14311 than the fuse146]) projects into the switch handle 143b, and the fuse 146111projecting farther into the switch handle 143b than the fuse 146Cprojects into the switch handle 143C.

While the switch handle 143e is of the same overall length as the switchhandles 14311 and 143b, the switch handle 143e is formed so that, incomparison with the switch handles 14311 and 143b, a portion of theperiphery defining the fuse receiving recess might be said to have beencut away, as at 168 in FIG. 13.

The base portions 12211, 122b, and 122e are formed respectively withprojections 17011, 170b, and 170e, respectively defining or ,providinginner surfaces 17111, 171b, and 171C. Further, the base portions 12211,12211, and 122e are formed respectively with inner surfaces 17211, 172b,and 172C as shown in FIGS. 1l, 12, and 13. The projection 170C isthicker than the projections 17011 and 170b, and the surfaces 17111 and171b are respectively disposed farther inwardly of the fuse-receivingopenings of the switches respectively having the base portions 12211 and12219 than the surface 171C is disposed inwardly of the fuse-receivin-gopening of the switch having the base portion 122C. Also, the surface17211 is disposed farther inwardly of the fuse-receiving opening of theswitch having the |base portion 12211 than the surfaces 172b and 1721`are respectively disposed inwardly of the fuse-receiving openings of theswitches respectively having the base portions 122b and 122C.

If a fuse 14611 or 146b is mounted in the switch handle 143C and theswitch handle and fuse are inserted in the switch having the baseportion 122C, the inner end of the fuse 14611 or 146b engages thesurface 172C before the projecting portion 4311 of the switch handle143C is disposed entirely inwardly of the surface 67 of the base portion122e, and the projecting portion 4311 interferes with the surface 65 ofthe base portion 122C to prevent the switch handle 143e from beingturned to the on position.

If either of the switch handles 14311 or 143k is inserted in the switchhaving the base portion 122C, it engages theA surface 171C before theprojecting portion 4311 thereof is disposed entirely inwardly of thesurface 67 of the base portion 122C, and the projecting .portion 4311interferes with the surface 65 of the base portion 122e to prevent theIswitch handle 14311 or 143b from being turned to the on position.Therefore, even if a fuse 146b is mounted in the switch handle 14311 toproduce a combination shorter than the overall length of the switchhandle 143C and a fuse 146C so as not to interfere with the surface 172Cof the base portion 122C, the combination of the fuse 146b .and switchhandle 14311 still cannot be turned to the on position in the baseportion 122C, due to the engagement of the switch handle 14311 with thesurface 171e before the projecting portion 4311 has cleared the surface67 of the base portion 1221'.

If any one of the switch handles 14311, 143k, and 143e and a fuse 14611mounted therein are inserted in the switch having the base portion 122b,the inner end of the fuse 14611 engages the surface 172b before theprojecting portion 4311 of the respective switch handle is disposedentirely inwardly of the surface 67 of the base portion 12211, and theprojecting portion 4311 interferes with the surface 65 of the baseportion 122b to prevent the respective switch handle from being turnedto the on position.

Therefore, it will be seen that no switch handle can be turned to an onposition in a particular switch when it has a fuse mounted therein of alarger current rating than intended for that switch. y

FIGS. 15 and 16 show an electrical panelboard 178 including anopen-front box 179, a cover secured to the front of the box, a door 181pivotally mounted on the cover, a trim panel 182 preferably, though notnecessarily, integral with the cover 181, and a mounting pan assemblyincluding a mounting pan 184 secured to a rear wall portion of the boXand having a pair of oppositely disposed mounting means such as mountingrails 185 formed integrally therewith, an insulating base 186 secured tothe mounting pan, a pair of main bus bars 187 secured to the insulatingbase in spaced parallel relationship, a plurality of branch bus bars188, each branch bus bar being secured to one of the main bus bars andeX- tending toward the other main bus bar and the branch bus bars beingalternately arranged so that each pair of consecutive branch bus barsare secured respectively to opposite main bus bars, a neutral barassembly 189 secured to the insulating base, a pair of electricalconnectors 190 for connecting Va pair of power lines respectively to themain bus bars, and a third electrical connector 190 for connecting amain neutral wire to the neutral bar assembly.

Shown interchangeably mounted on the mounting rails 185 and the branchbus bars 188 are a plurality of fusible switches 20 constructed inaccordance with this invention and a plurality of electrical circuitbreakers 192 constructed in accordance with the disclosure of theaforementioned U.S. Patent No. 3,134,051, the casings of the fusibleswitches 20 being of substantially the same size and shape as thecasings of the circuit breakers 192 and the mounting clip 40 andterminal jaws 49-50 of each of the fusible switches 2i) correspondingrespectively to the mounting clip 33 and terminal jaws 34 of the circuitbreaker of the aforementioned patent. In particular, the casings of thefusible lswitches 20 and the casings of the circuit breakers 192 eachhave a thickness substantially equal to but not greater than thedistance between the center lines of the branch bus bars 188. Further,the trim panel 182 is provided with a pair of openings 183 eachpartially defined by a pair of opposed parallel inner edge portions 183aand 18317, the casing of each fusible switch 20 is provided with agenerally rectangular projecting portion 21 having a dimensionsubstantially equal to but less than the distance between a pair of theedge portions 183a and 18S-b, and the casing of each circuit breaker 192is provided with a generally rectangular projecting portion 193 having adimension substantially equal to but no greater than the distancebetween a pair of the edge portions 183:1 and 183b. Thus, the fusibleswitches 20 Iand the electrical circuit breakers 192 are interchangeablymountable without alteration of the trim panel 183, and identicalpanelboards may be furnished by a manufacturer to each of two differentcustomers, one of whom prefers to use fusible switches and the other ofwhom prefers to use electrical circuit breakers.

Of the fusible switches 20 mounted in the electrical panelboard 178, onemay be considered to be of relatively high current rating, such as thefusible switch of FIG. l1, one of intermediate current rating, such asthe fusible switch of FIG. l2, and one of relatively low current rating,such as the fusible switch of FIG. 13.

It will be seen that we have provided an improved fusible switchsatisfying all the objects set forth before herein. Variousmodifications may Ibe made in the structure shown and described withoutdeparting from the spirit and scope of the invention.

We claim:

1. A fusible switch comprising a casing molded of electricallyinsulating material, a stationary Contact in said casing, an elongatedswitch handle formed of electrically insulating material and having aninner end portion disposed in said casing, said swtich handle beingmovable between ON and OFF positions, an electrically conductivecombination fuse clip and movable contact secured to said inner endportion of said switch handle and having a fuse clip portion which isadapted to receive an end portion of a cartridge fuse axially of thefuse and longitudinally of said switch handle and a movable contactportion which is disposed adjacent one side of said switch handletransversely thereof and engages said stationary contact when saidSwitch handle is in ON position, and a spring member in said casingengaging said switch handle transversely from a side thereof oppositesaid movable contact portion and establishing pressure between saidstationary contact and said movable contact portion when said movablecontact portion is in engagement with said stationary contact, saidswitch handle and a cartridge fuse acting as a rigid lever member whenan end portion of a cartridge fuse is installed in said fuse clipportion, and said spring member urging the rigid lever member formed bysaid switch handle and cartridge fuse pivotally about the other endportion of said cartridge fuse and being disposed farther from saidother end portion of said cartridge fuse than said movable contactportion so as to possess a mechanical advantage thereover and increasethe pressure between said stationary contact and said movable contactportion.

2. A fusible switch comprising a casing molded of electricallyinsulating material, a switch handle formed of electrically insulatingmaterial and having an inner end portion removably inserted in saidcasing, a generally cylindrical electrically conductive fuse clipsecured to said inner end portion of said switch handle and adapted toaxially receive a ferrule of a cartridge fuse having a cylindricalcasing closed at opposite ends respectively by a pair of ferrules, and aradially inwardly extending projection on a portion of-said fuse clippreventing complete removal of a fuse axially thereof from said fuseclip by interfering with an edge of said ferrule, said fuse clip havinga notched edge portion disposed generally opposite said projection andaccommodating tilting of said fuse in said fuse clip to allow said edgeof said ferrule to clear said projection for removal of said fuse fromsaid fuse clip.

3. A fusible switch as claimed in claim 2, wherein said fuse clip isprovided with a movable contact portion formed to extend outwardly ofthe remainder of said fuse clip and said notched edge portion resultsfrom the forming of said movable contact portion.

4. A fusible switch comprising a casing, a stationary contact in saidcasing, a switch handle formed of electrically insulating material andhaving an inner end p0rtion disposed in said casing, said switch handlebeing turnable to ON and OFF positions, an electrically conductivecombination fuse clip and pair of movable contacts secured to said innerend portion of said switch handle and having a fuse clip portion adaptedto receive and electrically engage an end portion of a cartridge fuseand a rst movable contact portion which engages said stationary contactin said ON position of said switch handle to complete a circuit througha cartridge fuse held by said fuse clip portion, and a spring membercooperable with said switch handle and acting as an indexing spring inthe turning of said switch handle between said ON and OFF positions,said combination fuse clip and pair of movable contacts having a secondmovable Contact portion engaging said spring member in said ON poSitionof said switch handle to complete a circuit through an indicating means.

5. A fusible switch comprising a casing, a stationary contact in saidcasing, a switch handle formed of electrically insulating material andhaving an inner end portion disposed in said casing, said switch handlebeing turnable to ON and OFF positions, an electrically condu-ctivecombination fuse clip and a pair of movable contacts secured to saidinner end portion of said switch handle and having a fuse clip portionadapted to receive and electrically engage an end portion of a cartridgefuse and a first movable contact portion which engages said stationarycontact in sai'cl ON position of said switch handle to complete acircuit through a cartridge fuse held by said fuse clip portion, aspring member cooperable with said switch handle and acting as anindexing spring in the turning of said switch handle between said ON andOFF positions, and an indicator lamp having a lead wire elec-tricallyconnected to said spring member, said combination fuse clip and pair ofmovable contacts having a second movable contact portion engaging saidspring member in said ON position of said switch handle to complete acircuit through said indicator lamp.

6. A fusible switch comprising a casing molded of electricallyinsulating material, a stationary contact in said casing, a switchhandle formed of electrically insulating material and having an innerend portion disposed in said casing, said switch handle being turnablein said casing to ON and OFF positions, an electrically conductivecombination fuse clip and pair of movable contacts secured to said innerend portion of said switch handle and having a fuse clip portion adaptedto receive and electrically engage an end portion of a cartridge fuseand a rst movable contact portion which engages said stationary contactin said ON position of said switch handle to complete a circuit througha cartridge fuse held by said fuse clip portion, a spring member in saidcasing cooperable with said switch handle and acting as an indexingspring in the turning of said switch handle between said ON and OFFpositions, a loadterminal strap in said casing having an outer endportion serving as a part of a load terminal, an inner end portionadapted to electrically engage the other end portion of a cartridge fuseheld by said fuse clip portion, and an intermediate portion having aresilient oifset tongue portion, and an indicator lamp in said casinghaving one lead wire electrically connected to said spring member andanother lead wire electrically connected to said resilient offset tongueportion of said load terminal strap by entrapment between said resilientoffset tongue portion and a portion of said casing, said combinationfuse clip and pair of movable contacts having a second movable contactportion engaging said spring member in said ON position of said switchhandle to complete a circuit through said indicator lamp.

'7. A fusible switch comprising a casing, a stationary Contact in saidcasing7 a switch handle formed of electrically insulating material andhaving an inner end portion disposed in said casing, said switch handlebeing disposable in said casing selectively in ON and OFF positions, anelectrically conductive fuse clip and pair of rst and second movablecontacts secured to said inner end portion of said switch handle, saidfuse clip being adapted to receive and electrically engage an endportion of a cartridge fuse, said rst movable contact engaging saidstationary contact in said ON position of said switch handle to completean electrical circuit through a cartridge fuse held by said fuse clip, aresilient electrical conductor in said casing, and an indicating lamp insaid casing, said indicating lamp having a lead wire electricallyconnected to said resilient electrical conductor, and said secondmovable contact engaging said resilient electrical conductor in said ONposition of said switch handle to complete an electrical circuit throughsaid indicating lamp.

8. The combination comprising an electrical panelboard and three fusibleswitches mounted therein, said three fusible switches being ofsubstantially the same Size and shape, respectively having relativelyhigh, intermediate, and low current ratings, and respectively beingadapted to receive three cartridge fuses respectively of relativelyhigh, intermediate, and low current ratings, each of said fusibleswitches including a casing molded of electrically insulating material,a stationary contact in said casing, a switch handle formed ofelectrically insulating material and having an inner end portionnormally disposed in said casing, said switch handle normally beingturnable in said casing alternatively to ON and OFF positions relativelythereto, and a'ri electrically conductive combination fuse clip andmovable contact secured to said inner end portion of said switch handleand having a fuse clip portion which is adapted to receive andelectrically engage an end portion of a cartridge fuse and a movablecontact portion which engages said stationary contact when said switchhandle is disposed in said casing in said ON position and is disengagedfrom said stationary contact when said switch handle is disposed in saidcasing in said OFF position, said switch handle being removablyinsertable in said casing and turnable to said ON position when a fuseof the current rating adapted to be received by the respective fusibleswitch is mounted in the fuse clip portion of the combination fuse clipand movable contact secured to the switch handle, each of the switchhandles of said three fusible switches having a portion which interfereswith a portion of the casing of the fusible switch of said intermedi-atecurrent rating to prevent turning of the switch handle to an ON positionin the casing of the fusible switch of said intermediate current ratingwhen a fuse of said high current rating is mounted in the fuse clipportion of the combination fuse clip and movable contact secured to theswitch handle and the switch handle with the fuse of said high currentrating mounted therein is inserted in the casing of the fusible switchof said intermediate current rating and an attempt is made to turn theswitch handle to said ON position, the switch handle of the fusibleswitch of said low current rating having a portion which interferes witha portion of the casing of the fusible switch of said low current ratingto prevent turning of the switch handle to an ON position in the casingof the fusible switch of said low current rating when one of the fusesof said high and lintermediate current ratings is mounted in the fuseclip portion of the combination fuse clip and movable contact secured tothe switch handle and the switch handle with one of the fuses of saidhigh and intermediate current ratings mounted thereon is inserted in thecasing of the fusible switch of said low current rating and an attemptis made to turn the switch handle to said ON position, and each of theswitch handles of the fusible switches of said high and intermediatecurrent ratings having a portion which interferes with a portion of thecasing of the fusible switch of said low current rating to preventturning of the switch handle to an ON position in the casing of thefusible switch of said low current rating when the switch handle isinserted in the casing of the fusible switch of said low current ratingand an attempt is made to turn the switch handle to said ON position.

9. The combination comprising an electrical panelboard and two fusibleswitches mounted therein, said two fusible switches being ofsubstantially the same size and shape, respectively having relativelyhigh and low current ratings, and respectively being adapted to receivetwo cartridge fuses respectively of relatively high and low currentratings, each of said fusible switches including a casing molded ofelectrically insulating material, a stationary contact in said casing, aswitch handle formed of electrically insulating material and having aninner end portion normally disposed in said casing, said switch handlenormally being turnable in said casing alternatively to ON and OFFpositions relatively thereto, and an electrically conductive combinationfuse clip and movable contact secured to said inner end portion of saidswitch handle and having a fuse clip portion which is adapted to receiveand electrically engage an end portion of a cartridge fuse and a movablecontact portion which engages said stationary contact when said switchhandle is disposed in said casing in said ON position and is disengagedfrom said stationary contact when said switch handle is disposed in saidcasing in said OFF position, said switch handle being removablyinsertable in said casing and turnable to said ON position when a fuseof the current rating adapted to be received by the respective fusibleswitch is mounted in the fuse clip portion of the combination fuse clipand movable contact secured to the switch handle, and the switch handleof the fusible switch of said lhigh current rating having a portionwhich interferes with a portion of the casing of the fusible switch ofsaid low current rating to prevent turning of the switch handle to an ONposition in the casing of the fusible switch of said low current ratingwhen the switch handle is inserted in the casing of the fusible switchof said low current rating and an attempt is made to turn the switchhandle to said ON position.

References Cited UNITED STATES PATENTS 1,683,598 9/1928 Benoit 200-1191,927,335 9/1933 Cole 200-121 1,966,716 7/1934 Green 200-114 2,417,6923/ 1947 Kline 200-129 2,929,966 3/1960 Bangert 317-119 3,134,051 5/1964Lyon 317-119 3,225,164 12/ 1965 Linton 200-121 3,286,061 11/1966Henderson 200-114 FOREIGN PATENTS 402,386 4/ 1909 France. 431,840 6/1911France.

BERNARD A. GILHEANY, Primary Examiner.

E. SPRINGBORN, Assistant Examiner.

2. A FUSIBLE SWITCH COMPRISING A CASING MOLDED OF ELECTRICALLYINSULATING MATERIAL, A SWITCH HANDLE FORMED OF ELECTRICALLY INSULATINGMATERIAL AND HAVING AN INNER END PORTION REMOVABLY INSERTED IN SAIDCASING, A GENERALLY CYLINDRICAL ELECTRICALLY CONDUCTIVE FUSE CLIPSECURED TO SAID INNER END PORTION OF SAID SWITCH HANDLE AND ADAPTED TOAXIALLY RECEIVE A FERRULE OF A CARTRIDGE FUSE HAVING A CYLINDRICALCASING CLOSED AT OPPOSITE ENDS RESPECTIVELY BY A PAIR OF FERRULES, AND ARADIALLY INWARDLY EXTENDING PROJECTION ON A PORTION OF SAID FUSE CLIPPREVENTING COMPLETE REMOVAL OF A FUSE AXIALLY THEREOF FROM SAID FUSECLIP BY INTERFERING WITH AN EDGE OF SAID FERRULE, SAID FUSE CLIP HAVINGA NOTCHED EDGE PORTION DISPOSED GENERALLY OPPOSITE SAID PROJECTION ANDACCOMMODATING TILTING OF SAID FUSE IN SAID FUSE CLIP TO ALLOW SAID EDGEOF SAID FERRULE TO CLEAR SAID PROJECTION FOR REMOVAL OF SAID FUSE FROMSAID FUSE CLIP.